Abstract

Ethidium bromide is a strong mutagen and is also very toxic at acute exposures. It is classified as a potent mutagen. Therefore, the main aim of this research is to study the efficiency of raw and modified pumice in the adsorption of Ethidium bromide from synthetic solutions. Initially, the pumice used in the present study was kept in 0.1 N HCl for 24 hours. Thereafter, it was washed repeatedly with distilled water and was oven dried at 105°C for 24 hours. Then, the dried samples were ground and were passed through 20-30 mesh sieves with effective size of 2-3 mm. The floating method was used to coat zinc and titanium dioxide nanoparticles onto the adsorbent. A spectrophotometer was used to determine the concentration of Ethidium bromide based on the absorption at the wavelength of 285 nm. The results showed that as contact time increases, the adsorption capacities of the three adsorbents also increase. The equilibrium time was determined to be 60 min for used adsorbents. The equilibrium adsorption data tended to fit with the second pseudo order kinetic. Adsorption rate constants (K 2 ) for modified pumice with TiO 2 and ZnO were several times more in comparison with raw pumice. The results showed that by coating TiO 2 and ZnO onto raw pumice, the adsorption capacity and also adsorption rate were significantly increased. Moreover, pumice modified with ZnO showed a more adsorption capacity than pumice modified with TiO 2 .